bug#19116: 25.0.50; doc string of `eval-expression'

[Drew Adams]

> > The doc string says only what this function does "When called
> > interactively".  It says nothing about what it does when called from
> > Lisp.  Please complete the description of the function, to take care of
> > this.
> 
> This is how the doc starts:
> 
> Evaluate EXP and print value in the echo area.
> When called interactively, read an Emacs Lisp expression and evaluate it.
> 
> So I see no need to change anything here.

Doc for commands should present the behavior first in terms
of interactive use - as a command, for all users.

Only after that should it describe use of the command from
Lisp code.

The first line of the doc string should not be the first line
of the doc string.